HONG KONG, May 13 (Reuters) - Malaysian long-haul budget carrier AirAsia X said it is looking to raise $300 million in an IPO, throwing its hat into an expanding fundraising ring as Southeast Asian airlines seek to build up their fleets and ride a boom in regional passenger traffic.

The funds will help AirAsia to repay debt as well as pay for existing planes and aircraft on order. The airline is keen to set up a second base in Thailand that will allow it to deploy more aircraft in different areas.

Other airlines planning listings this year include Nok Airlines, a unit of Thai Airways, Bangkok Airways as well as AirAsia X’s sister company Indonesia AirAsia. Those three listings combined are expected to raise up to $600 million. Further down the road, Indonesia’s largest domestic airline Lion Air plans to go public in 2015.

Passenger traffic in the Asia Pacific region has more than doubled between 1998 and 2012, putting air travel activity in the region on par with North America, according to figures from research firm Strategic Airport Planning Ltd which were cited in AirAsia X’s preliminary prospectus.

Fueling these expansion plans has been a surge in economic activity for Southeast Asian nations as well as in investor interest that is supporting IPOs across a wide range of sectors.

Travel on airline routes within and from the region in the 20 years to 2031 is forecast to outpace the global average rate for growth.

For example, travel within Southeast Asia is forecast to grow 7.6 percent a year in the period, while travel between Southeast Asia and South Asia is expected to grow 9.5 percent a year compared with a global average of 5 percent, according to the estimates in the prospectus.

AirAsia X, founded by entrepreneur Tony Fernandes, and its shareholders are offering 790.1 million shares, with 75 percent of the offering coming from new shares, according to a term sheet of the deal seen by Reuters on Monday. Pricing is slated for June 24, and its debut is set for July 10.

The IPO was originally planned for the first quarter of the year, but was postponed due to Malaysia’s elections and volatility in global markets.

AirAsia X plans to use 44 percent of the proceeds to repay bank loans, with another 22 percent set for capital expenditures, the terms said.

CIMB, Credit Suisse, Maybank and Morgan Stanley were hired as joint global coordinators on the IPO.

Barclays, BNP Paribas, Citigroup, CLSA, HSBC will also act as joint bookrunners of the deal.